CCTV Storage Calculator
Professional capacity planning for IP cameras, NVRs, and DVR systems. Accurately calculate required hard drive Terabytes based on camera channels, resolution, retention days, motion percentage, and RAID parity.
Last Updated: November 4, 2026
Surveillance Resolution & Storage Reference Matrix (Per Camera)
Bandwidth estimates per camera at standard 20 FPS assumed baseline. H.264/H.265 are model estimates; H.265+ Smart Codec savings (50–70%) represent manufacturer vendor claims (Hikvision / Dahua) ↗:
| Camera Resolution (Assumed 20 FPS) | Megapixels | H.264 (Estimate) | H.265 (Estimate) | H.265+ (Vendor Claim) | Daily Storage (H.265) | 30-Day Storage (H.265) |
|---|---|---|---|---|---|---|
| 2MP / 1080p Full HD (20 FPS) | 2.07 MP | 4.0 Mbps estimate | 2.0 Mbps estimate | 0.9 Mbps vendor claim | 21.6 GB / day | 0.65 TB |
| 3MP Super HD (20 FPS) | 3.15 MP | 6.0 Mbps estimate | 3.0 Mbps estimate | 1.4 Mbps vendor claim | 32.4 GB / day | 0.97 TB |
| 4MP / 2K Quad HD (20 FPS) | 3.69 MP | 8.0 Mbps estimate | 4.0 Mbps estimate | 1.8 Mbps vendor claim | 43.2 GB / day | 1.30 TB |
| 5MP Super HD (20 FPS) | 5.04 MP | 10.0 Mbps estimate | 5.0 Mbps estimate | 2.3 Mbps vendor claim | 54.0 GB / day | 1.62 TB |
| 6MP Ultra HD (20 FPS) | 6.29 MP | 12.0 Mbps estimate | 6.0 Mbps estimate | 2.8 Mbps vendor claim | 64.8 GB / day | 1.94 TB |
| 8MP / 4K Ultra HD (20 FPS) | 8.29 MP | 16.0 Mbps estimate | 8.0 Mbps estimate | 3.7 Mbps vendor claim | 86.4 GB / day | 2.59 TB |
| 12MP Panoramic / Fisheye (20 FPS) | 12.00 MP | 24.0 Mbps estimate | 12.0 Mbps estimate | 5.5 Mbps vendor claim | 129.6 GB / day | 3.89 TB |
Why Desktop HDDs Fail in CCTV NVR Systems
Installing commercial desktop hard drives (e.g. WD Blue, Seagate BarraCuda) in a security recorder is the leading cause of premature storage failure and missing incident footage:
- • Workload Profile: 80% Read / 20% Write (designed for light office use).
- • Duty Cycle: 8 hours/day, 5 days/week (intermittent spinning).
- • Workload Rating: Only 55 TB/year.
- • No Vibration Dampening: Hard drive actuator heads lose track alignment in multi-drive enclosures due to harmonic vibration.
- • Standard Error Recovery: Freezes video recording for up to 30 seconds when attempting to recover a bad sector, dropping live camera feeds.
- • Workload Profile: 90% Write / 10% Read (optimized for video ingestion).
- • Duty Cycle: 24/7/365 continuous operation without thermal degradation.
- • Workload Rating: 180 TB/year (up to 550 TB/year on enterprise tiers).
- • Built-in RV Sensors: Rotational vibration sensors protect drive performance in 4-bay to 16-bay NVR racks.
- • ATA Streaming Firmware: Prioritizes uninterrupted video writes over error correction, guaranteeing zero dropped surveillance frames.
Accounting for RAID Parity Overhead
Commercial surveillance systems protecting banks, retail, and campuses utilize hardware RAID arrays to guarantee data survival:
- • RAID 1 (Mirror): Consumes 50% of raw disk capacity for exact mirroring.
- • RAID 5 (Distributed Parity): Requires minimum 3 drives. Deducts 1 drive for parity (e.g. 4 × 8TB drives = 24TB usable).
- • RAID 6 (Dual Parity): Requires minimum 4 drives. Deducts 2 drives for dual parity, safely surviving 2 simultaneous disk failures during intensive rebuilds.
- • RAID 10 (Striped Mirror): 50% storage overhead, but provides the fastest rebuild times and highest I/O write throughput.
Capacity Sizing Rule (Plain Fact): The ~9% gap between decimal Terabytes (TB, 10^12 bytes, used by drive manufacturers) and binary Tebibytes (TiB, 2^40 bytes, used by operating systems) is a mathematical decimal/binary unit difference (1 TB ≈ 0.909 TiB), not filesystem overhead. Hardware RAID parity is handled strictly by physical drive count geometry (N-1 or N-2). Parity is applied once only via disk count geometry, and is never counted a second time.
Continuous Recording vs Motion Detection
Configuring cameras to record exclusively upon motion detection can reduce required hard drive capacity by 50% to 70%. However, professional installers must account for pre-event and post-event buffering (saving 5 seconds before and after motion events) and camera background metadata streams.